(1) Field of the Invention
The present invention is in the field of memory access; more specifically, the present invention is related to a method and apparatus for an overlay counter for an accelerated graphics port.
(2) Related Art
A typical graphics device in a computer system has expedited priority in accessing a system memory over other system devices. In currently available systems, lower priority devices must wait their turn to access the system memory. Because a graphics device is assigned expedited priority, a graphics device may indirectly cause other devices vying for access to the system memory to fail by depriving them of access time. However, in order to output graphics information to a user in a timely fashion, it is imperative for the graphics device to maintain its expedited priority status.
It is therefore desirable to provide a method and an apparatus to allow system memory access requests by other devices to be honored without jeopardizing expedited priority status of a graphics device.